Conventionally, as exhaust cleaning systems using filters for clarifying and discharging exhaust air containing oily steam and dust generated from the kitchens used at food supply facilities of hotels, restaurants, Tempura restaurants and Yakitori restaurants and home ventilation fans, and exhaust air containing contaminants generated from incineration facilities at waste incineration plants, crushing facilities of quarries and clinker calcination facilities of cement plants, various compositions are known. With regard to exhaust cleaning systems provided at kitchens, for example, compositions shown in FIGS. 20 and 21 are known.
A kitchen systems shown in FIGS. 20 and 21 employs a composition that an exhaust cleaning system 205 having a filter 204, such as a grease filter or a grease separator, for separating and removing tarry matters containing oil/grease and dust from an exhaust air 203 is arranged in a bellmouth-shaped hood 202 expanding downward that is connected to an exhaust duct 201, which is connected to the outdoors and stores a fan, and is arranged in a ceiling.
The filter 204 is, as provided by the Fire Service Law and various technical standards, formed with a stainless steel sheet, or a noncombustible material having a heat resistance and a corrosion resistance equal to or higher than those of the stainless steel sheet. In addition, the filter 204 is, as shown in FIG. 22 through 25, formed as a louver structure which a rapid directional conversion and contraction in air flow that occur when the exhaust air 203 flows through. And by a rapid directional conversion and contraction in air flow an oil/grease content in the exhaust air 203 touches a wall surface and an oil content exceeding a prescribed quantity is removed. Further, the filter 204 is arranged with a formation facilitating mounting/dismounting so that a deposited oil/grease can easily be washed off by separation. Underneath the filter 204, a trough 207 for collecting an oil/grease that flows through along an inner wall surface provided around a bottom part of the hood 202, and a trough 208 for collecting a prescribed quantity or more of the separated oil/grease and removing the same outside the hood 202 are provided. Additionally, the exhaust cleaning system 205 is arranged in the hood 202 such that a plain of the filter 204 is approximately 45 degrees tilted in conjunction with a horizontal plain so as to surely collect an oil/grease without causing dropping to a combustion system 210 and a fire source 211 in a kitchen.
Meantime, in the case of the exhaust cleaning system 205 having the filter 204 with the louver structure as shown in FIG. 22 through 25, an oil/grease content in the exhaust air 203, when it exceeds the prescribed quantity, flows out and is collected by troughs 207 and 208 arranged at the lower part. However, in the case of the filter 204 with the louver structure, when the exhaust air 203 contains a tar matter containing dust, the oil/grease content becomes stagnant due to an increase in viscosity, causing a decrease in flowability of the exhaust air 203 and in separation/removal efficiency. Also, as a noise, such as an air sound, is generated, a cleaning operation of the filter 204 using an alkali detergent must be done frequently particularly in an environment containing a lot of oil/grease. Further, an oil/grease content that is not removed and flows through the filter 204 deposits to an inner wall surface of the exhaust duct 201, degrading its exhaustibility, and the oil/grease deposited to the inner wall surface of the exhaust duct 201 adheres in a tar form due to a deposit of dust. Moreover, since this tar formed oil/grease requires a troublesome removal operation and involves a danger of ignition when it is oxidized, a troublesome cleaning operation of the exhaust duct 201 must be done. This increases a cleaning cost.
Also, when a fire prevention system, such as a fire damper or a fire extinguishing system having fire nozzles, is arranged in the exhaust duct 201, an oil/grease content that is not removed and flows through deposits and might hinder a fire extinguishing operation. Since maintenance is troublesome, a problem is an increase in maintenance cost.
To cope with this, conventionally, contaminants is separated and removed by spraying a cleaning detergent to a flowing exhaust air, contaminants depositing to the filter 204 is washed off by spraying a cleaning detergent to the filter 204, or a grease extractor providing an automatic cleaning function such as to separate and remove contaminants by flowing an exhaust air through a cleaning detergent or water is used.
However, in the case of a grease extractor providing an automatic cleaning function with a composition such that a cleaning liquid is sprayed or is blown to the filter 204, it is necessary to collect an effluent containing a washed oil/grease that flows through inside the exhaust duct 201 or nozzle for spraying or blowing without disturbing a flow of the exhaust air 203. The structures are complicated, making the production complicated and expensive and the system becomes a large scale. Further, in the case of a composition by which an exhaust air is flown through a cleaning liquid or water, it is necessary to take a long time for contact with a cleaning liquid or water to increase a removal rate, which poses a problem that a large air path resistance is generated and it is not possible to efficiently clean the exhaust air.
Also, because of a fixed composition to be attached to the hood 202, when cooking using oil is done at a center of a kitchen, for example, a collection rate of an evaporated oil/grease absorbed from the hood is extremely decreased, posing a problem of a degradation in a cooking environment.
Further, in a household environment containing an evaporated oil/grease a little, a problem is a difficulty to secure a space to arrange the hood 202 into which the exhaust cleaning system 205 is attached.
It is an object, therefore, of the present invention to provide an exhaust cleaning system of which a cleaning of a filter, that is soiled by cleaning exhaust air, is almost unnecessary and a maintenance is made easy: an exhaust cleaning system that can efficiently clean exhaust air; an exhaust cleaning system with a simple composition that can easily be produced; an exhaust cleaning system that can thoroughly clean particularly an exhaust air containing oil/grease; an exhaust cleaning system that can be moved as required by a style of use; and a compact exhaust cleaning system suitable for a use environment.